The present invention generally relates to vacuum relief valves. More particularly, the present invention relates to a vacuum relief safety valve for use in swimming pools, spas and the like which causes the pump to lose its prime if a pre-determined vacuum level is reached in the pump system, such as when an object obstructs the pool's drain.
To maximize enjoyment and maintain proper sanitary conditions, swimming pools must be constantly cleaned of debris, dirt and other contaminants. Pools of various types are known to have one or more suction inlets where pool water is sucked along the line via a pump to filtration, aeration, chemical treatment and other type of equipment prior to being returned to the pool via one or more return outlets.
In more recent pool designs, some of the suction inlets are positioned in the bottom or lower region of the pool. Very recently developed pool systems, known as in-floor cleaning systems, have one or more suction inlets which suck pool water therethrough and any debris of pollutants entrained therein are cleaned from the water by being pumped through a filtration and/or treatment station. As with all pools and spas, a high rate of water flow must be achieved in order to maintain an acceptable level of cleanliness. Consequently, a high capacity pump must be employed to draw the water from the pool, with a relatively larger pump generally being required as the size of the pool increases.
Some of the water inlets of such drains have relatively small opening areas and, when large volumes of water being pumped therethrough, very high suction forces at the inlet can be induced. These forces can be so extreme that if a pool user contacts the inlet by any part of their body, they can be held thereagainst, unable to be dislodged, even by excessive force. Such vacuum forces have become so excessive that there have been cases of disembowelment. When the suction inlet is located at or more adjacent to the bottom of a pool, the user can thus be submerged with the risk of drowning or other grievous injury. When such an incident occurs, the vacuum level in the drain line and pool's pump rises sharply.
Occurrences of this type of accident has caused the pool industry to look for solutions that prevent an individual, such as a child, from becoming entrapped at the drain. Some approaches have been by modifying the drain's construction. Examples of this approach include U.S. Pat. No. 5,809,587 to Fleischer and U.S. Pat. No. 6,295,661 to Bromley. However, these devices are fairly complex and expensive to produce. Moreover, these approaches are only acceptable for new pool construction, and are not capable of being incorporated as a retrofit into existing pools and spas.
Yet other approaches involve the insertion of a safety valve into a section line of the filtration pump system. Examples of these include, U.S. Pat. No. 5,682,624 to Ciochetti; U.S. Pat. No. 6,591,863 to Ruschell et al.; and U.S. Pat. No. 6,687,923 to Dick et al. However, this approach also presents many drawbacks. First, such piping is typically submerged below the ground and often encased in or otherwise positioned below concrete. Thus, access to the pipes is not readily obtained unless the safety valve is incorporated into the system when the swimming pool is built. Otherwise, the valves require that the pipe be cut so that the safety valve device can be inserted therein. Cutting these lines increases the opportunity for air leakage in the suction side. Moreover, such installation typically requires professionals having the appropriate tools and ability to install such safety devices.
Oftentimes, these devices also require calibration by experimentation at the pool site such that the safety valve opens only in an excessive vacuum situation. For example, U.S. Pat. No. 5,682,624 includes a manual turn screw for calibrating the valve assembly at the pool site. However, vacuum levels of a specific pump can change from one day to another due to many factors. Moreover, such manual calibration is dangerous if a child were to turn the knob and adjust the calibration such that the safety device did not work properly. Another problem with the '624 device is that it includes many openings which can be filled with water, dirt, insects and other debris. A problem with all such “in-line” systems is that they are typically not close to the pump. The closer one gets to the pump, the better the safety device responds to emergencies.
Accordingly, there is a continuing need for a pool safety valve which overcomes the deficiencies described above. The safety valve should be capable of being attached directly to the pump. The safety valve should also be simple enough in design so as to be manufactured inexpensively and installed by the pool owner. The safety valve should also be capable of being used in existing pools as a retrofit. The present invention fulfills these needs and provides other related advantages.